Apparatus and method for communication using wireless power

ABSTRACT

An apparatus and method for communication using a wireless power are provided. The apparatus includes an amplifier configured to amplify an input signal based on a power supplied to the amplifier. The apparatus further includes a control unit configured to detect a change in an impedance of a target device, and to change the power based on the change in the impedance. The apparatus further includes a demodulation unit configured to receive a message from the target device, and to demodulate the message based on the changed power.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 U.S.C. §119(a) of KoreanPatent Application No. 10-2011-0052180, filed on May 31, 2011, in theKorean Intellectual Property Office, the entire disclosure of which isincorporated herein by reference for all purposes.

BACKGROUND

1. Field

The following description relates to an apparatus and method forcommunication using a wireless power.

2. Description of Related Art

Wireless power transmission may overcome problems, such as, for example,the inconvenience of wired power supplies, and limits to existingbattery capacities, with respect to various electronic devicesincluding, for example, electric vehicles, mobile devices, and/or thelike. Wireless power transmission may use resonance characteristics ofradio frequency (RF) elements. For example, a wireless powertransmission system using resonance characteristics may include a sourcedevice configured to supply power, and a target device configured toreceive the supplied power.

SUMMARY

In one general aspect, there is provided an apparatus for communicationusing a wireless power, including an amplifier configured to amplify aninput signal based on a power supplied to the amplifier. The apparatusfurther includes a control unit configured to detect a change in animpedance of a target device, and to change the power based on thechange in the impedance. The apparatus further includes a demodulationunit configured to receive a message from the target device, and todemodulate the message based on the changed power.

The apparatus further includes a detection unit configured to detect thechanged power.

The detection unit further includes a resistor, or an ON-resistance of atransistor, or a line impedance, or any combination thereof. Thedetection unit is further configured to detect a voltage applied to theresistor, or the ON-resistance of a transistor, or the line impedance,or any combination thereof, to detect the changed power.

The demodulation unit includes an amplification unit configured toamplify the changed power to be greater than a predetermined value.

The demodulation unit includes a ripple signal removing unit configuredto remove a ripple signal included in the changed power.

The demodulation unit includes a comparison unit configured to comparethe changed power to a predetermined reference signal, and to determinea HIGH value or a LOW value of the changed power based on a result ofthe comparison. The demodulation unit is further configured todemodulate the message based on the HIGH value or the LOW value.

In another general aspect, there is provided an apparatus forcommunication using a wireless power, including an amplifier configuredto amplify an input signal based on a direct current (DC) voltage of aplurality of levels that is supplied to the amplifier. The apparatusfurther includes a control unit configured to control the DC voltage.The apparatus further includes a modulation unit configured to modulatedata based on the controlled DC voltage.

The apparatus further includes a conversion unit configured to receivean alternating current (AC) voltage, and to convert the AC voltage tothe DC voltage based on a switching pulse signal.

The amplifier is further configured to output a power based on theamplified signal. The modulation unit is further configured to modulatethe data based on an index of the power.

The control unit is further configured to generate a digital controlsignal, to convert the digital control signal to an analog controlsignal, and to control the DC voltage based on the analog controlsignal.

The control unit is further configured to control a pulse width of theDC voltage.

The amplifier is further configured to receive an input voltage and anoperational voltage. The control unit is further configured to control amagnitude of the input voltage or a magnitude of the operationalvoltage.

In still another general aspect, there is provided a method forcommunication using a wireless power, including detecting a change in animpedance of a target device. The method further includes changing apower supplied to an amplifier based on the change in the impedance. Themethod further includes demodulating a message received from the targetdevice based on the changed power.

The method further includes detecting the changed power.

The demodulating includes amplifying the changed power to be greaterthan a predetermined value.

The demodulating includes comparing the changed power to a predeterminedlevel, determining a HIGH value or a LOW value of the changed powerbased on a result of the comparing, and demodulating the message basedon the HIGH value or the LOW value.

In yet another general aspect, there is provided a method forcommunication using a wireless power, including controlling a directcurrent (DC) voltage of a plurality of levels that is supplied to anamplifier. The method further includes modulating data based on thecontrolled DC voltage.

The method further includes converting an alternating current (AC)voltage to the DC voltage based on a switching pulse signal.

The modulating includes modulating the data based on an index of a poweroutput from the amplifier.

The controlling includes generating a digital control signal, convertingthe digital control signal to an analog control signal, and controllingthe DC voltage based on the analog control signal.

The controlling includes controlling a pulse width of the DC voltage.

Other features and aspects may be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless powertransmission system.

FIG. 2 is a diagram illustrating an example of a communication apparatususing a wireless power.

FIG. 3 is a diagram illustrating a detailed example of a communicationapparatus using a wireless power.

FIG. 4 is a diagram illustrating another example of a communicationapparatus using a wireless power.

FIG. 5 is a diagram illustrating another detailed example of acommunication apparatus using a wireless power.

FIG. 6 is a diagram illustrating still another example of acommunication apparatus using a wireless power.

FIG. 7 is a diagram illustrating an example of a modulation unit.

FIG. 8 is a diagram illustrating another example of a modulation unit.

FIG. 9 is a graph illustrating an example of a relationship between avoltage that is supplied to a power amplifier and a power that is outputfrom the power amplifier.

FIG. 10 is a diagram illustrating an example of a modulating processusing a power that is output from a power amplifier.

FIG. 11 is a flowchart illustrating an example of a communication methodusing a wireless power.

FIG. 12 is a flowchart illustrating another example of a communicationmethod using a wireless power.

FIG. 13 is a diagram illustrating an example of an electric vehiclecharging system.

FIGS. 14A through 15B are diagrams illustrating examples of applicationsin which a wireless power receiver and a wireless power transmitter maybe mounted.

FIG. 16 is a diagram illustrating an example of a wireless powertransmitter and a wireless power receiver.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features, and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. Accordingly, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be suggested to those of ordinary skill inthe art. The progression of processing steps and/or operations describedis an example; however, the sequence of and/or operations is not limitedto that set forth herein and may be changed as is known in the art, withthe exception of steps and/or operations necessarily occurring in acertain order. Also, description of well-known functions andconstructions may be omitted for increased clarity and conciseness.

FIG. 1 illustrates an example of a wireless power transmission system.The wireless power transmission system includes a source device 110 anda target device 120. The source device 110 includes a device supplying awireless power, and may include all sorts of electric devices thatsupply a power, such as, for example, pads, terminals, televisions(TV's), and/or other types of devices. The target device 120 includes adevice receiving a wireless power, and may include an all sorts ofelectronic devices that consume a power, such as terminals, TV's,vehicles, washing machines, radios, lighting systems, and/or other typesof devices.

The source device 110 includes an alternating current-to-direct current(AC/DC) converter 111, a power supply 112, a power detector 113, a powerconverter 114, a control and communication (control/communication) unit115, and a source resonator 116. The target device 120 includes a targetresonator 121, a rectification unit 122, a DC-to-DC (DC/DC) converter123, a switch unit 124, a charging unit 125, and a control/communicationunit 126.

The AC/DC converter 111 rectifies an AC voltage output from the powersupply 112 to generate a DC voltage. The AC/DC converter 111 may outputthe DC voltage of a predetermined level, or may adjust an output levelof the DC voltage, based on control of the control/communication unit115.

The power detector 113 detects an output current and an output voltageof the AC/DC converter 111, and transfers, to the control/communicationunit 115, information on the detected current and the detected voltage.The power detector 113 may detect an input current and an input voltageof the power converter 114.

The power converter 114 converts the DC voltage to an AC voltage togenerate a power, using a switching pulse signal in a band of a fewmegahertz (MHz) to tens of MHz. The power converter 114 converts the DCvoltage to the AC voltage using a resonance frequency, and thus,generates a communication power to be used for communication and/or acharging power to be used to charge in the target device 120. Forexample, the communication power may correspond to energy to activate aprocessor and a communication module of the target device 120. Further,the communication power may be referred to as a wake-up power. Thecommunication power may be transmitted in a form of a constant waveduring a predetermined time. In another example, the charging power maycorrespond to energy to charge a battery connected to or included in thetarget device 120. Further, the charging power may be continuouslytransmitted during a predetermined time, and may be transmitted at apower level greater than a power level of the communication power.

The control/communication unit 115 controls the resonance frequency ofthe switching pulse signal. That is, the resonance frequency of theswitching pulse signal is determined based on the control of thecontrol/communication unit 115. By controlling the power converter 114,the control/communication unit 115 generates a modulated signal to betransmitted to the target device 120. The control/communication unit 115may transmit various messages to the target device 120 through anin-band communication. The control/communication unit 115 detects areflected wave, and demodulates a signal received from the target device120 through an envelope of the detected reflected wave.

The control/communication unit 115 may generate the modulated signal forthe in-band communication, using various schemes. For example, togenerate the modulated signal, the control/communication unit 115 mayturn the switching pulse signal ON and OFF, or may perform delta-sigmamodulation. Additionally, the control/communication unit 115 maygenerate a pulse-width modulated (PWM) signal having a predeterminedenvelope.

The control/communication unit 115 may perform an out-band communicationusing a communication channel, as opposed to using the resonancefrequency. The control/communication unit 115 may include acommunication module, such as, for example, a ZigBee module, a Bluetoothmodule, and other types of modules. The control/communication unit 115may perform transmission and reception of data with the target device120 through the out-band communication.

The source resonator 116 transfers an electromagnetic energy to thetarget resonator 121. For example, the source resonator 116 transfers,to the target device 120, the communication power and/or the chargingpower through a magnetic coupling with the target resonator 121.

The target resonator 121 receives the electromagnetic energy from thesource resonator 116. For example, the target resonator 121 receives,from the source device 110, the communication power and/or the chargingpower through a magnetic coupling with the source resonator 116. Thetarget resonator 121 may receive various messages from the source device110 through the in-band communication.

The rectification unit 122 rectifies an AC voltage received from thetarget resonator 121 to generate a DC voltage The DC/DC converter 123adjusts a level of the DC voltage output from the rectification unit 122based on a capacity of the charging unit 125. For example, the DC/DCconverter 123 may adjust the level of the DC voltage to be within arange of 3 Volts (V) to 10V.

The switch unit 124 is turned ON and OFF based on a control of thecontrol/communication unit 126. When the switch unit 124 is turned OFF,the control/communication 115 of the source device 110 detects thereflected wave. When the switch unit 124 is turned OFF, the magneticcoupling between the source resonator 116 and the target resonator 121is eliminated.

The charging unit 125 may include a battery. The charging unit 125 maycharge the battery using the DC voltage output from the DC/DC converter123.

The control/communication unit 126 may perform the in-band communicationto transmit and receive data using the resonance frequency. In thisexample, the control/communication unit 126 may demodulate a receivedsignal by detecting a signal between the target resonator 121 and therectification unit 122, or by detecting an output signal of therectification unit 122. The control/communication unit 126 maydemodulate a message received through the in-band communication. Also,the control/communication unit 126 may adjust an impedance of the targetresonator 121 to modulate a signal to be transmitted to the sourcedevice 110. The control/communication unit 126 may turn the switch unit1240N and OFF to modulate the signal to be transmitted to the sourcedevice 110. For example, the control/communication unit 126 may increasethe impedance of the target resonator 121 so that thecontrol/communication unit 115 of the source device 110 detects thereflected wave. In this example, depending on whether the reflected waveis detected, the control/communication unit 115 may detect a binaryvalue of “0” or “1”.

The control/communication unit 126 may perform the out-bandcommunication using the communication channel. The control/communicationunit 126 may include, for example, a communication module, such as aZigBee module, a Bluetooth module, and/or other types of modules. Thecontrol/communication 126 may perform transmission and reception of datawith the source device 110 through the out-band communication.

FIG. 2 illustrates an example of a communication apparatus using awireless power. The communication apparatus may be implemented in thesource device 110 of FIG. 1. Referring to FIG. 2, the communicationapparatus includes a frequency generating unit 210, a power amplifier(PA) 220, a detection unit 240, an AC/DC converter 250, a demodulationunit 260, and a control unit 270.

The frequency generating unit 210 generates a signal with a resonancefrequency. The resonance frequency is determined by the control unit270. To determine the resonance frequency, the control unit 270 matchesimpedances between a source device and a target device.

The PA 220 amplifies the input signal with the resonance frequency to amagnitude (e.g., of amplitude) corresponding to a request of the targetdevice. The request of the target device may be determined based on animpedance 230 of the target device. The impedance 230 of the targetdevice includes an impedance viewed from a direction of the sourcedevice to the target device. Also, a power corresponding to the requestof the target device may be determined based on a power supplied to thePA 220 from the AC/DC converter 250. An amount of the power supplied tothe PA 220 may be calculated by measuring a supplied voltage or asupplied current.

A process in which the target device modulates a message by changing animpedance of the target device may be referred to as load modulation.When the impedance 230 of the target device is changed, the powersupplied to the PA 220 is changed based on the change in the impedance230. Accordingly, the change in the impedance 230 of the target devicemay be estimated by measuring the supplied voltage or the suppliedcurrent.

For example, the detection unit 240 detects the power supplied to the PA220. In this example, the detection unit 240 may detect the voltage orthe current supplied to the PA 220. In the following descriptions, adetected supplied power may refer to a detected supplied voltage or adetected supplied current.

In other examples, the detection unit 240 may detect the power suppliedto the PA 220 by detecting a voltage applied to both ends of a resistor.The detection unit 240 may detect the power supplied to the PA 220, bydetecting a current flowing through the resistor. Also, the detectionunit 240 may detect the power supplied to the PA 220, by detecting avoltage applied to both ends of an On-resistance (R_(on)) of atransistor. The detection unit 240 may detect the power supplied to thePA 220, by detecting a current flowing through the On-resistance.Further, the detection unit 240 may detect the power supplied to the PA220, by detecting a voltage applied to both ends of a line impedance.The detection unit 240 may detect the power supplied to the PA 220, bydetecting a current flowing through the line impedance.

The AC/DC converter 250 generates the power supplied to the PA 220. Togenerate the power, the AC/DC converter 250 rectifies an AC signal from,e.g., a power supply, to convert the AC signal to a predetermined DCsignal. When the impedance 230 of the target device is changed, thecontrol unit 270 senses the changed impedance, and controls a matchingnetwork of the source device to match the impedance of the source deviceto the changed impedance. Also, the control unit 270 controls the powerthat is output from the AC/DC converter 250 to be a power correspondingto the request of the target device. The power output from the AC/DCconverter 250 is provided to the PA 220 as the supplied power to the PA220.

The demodulation unit 260 demodulates a message received from the targetdevice based on a change in an amount of the detected supplied power.Since the power supplied to the PA 220 is changed based on the change inthe impedance 230 of the target device, the demodulation unit 260demodulates the message by comparing the change in the amount (e.g., asignal) of the detected supplied power to a predetermined referencesignal.

In more detail, the demodulation unit 260 includes an amplification unit261, a ripple removing unit 263, and a comparison unit 265. Theamplification unit 261 amplifies the detected supplied power to begreater than a predetermined value. The amplification unit 261 amplifiesthe detected supplied power so that the demodulation unit 260 maydemodulate the message based on the detected supplied power, even thougha value of a resistance of the detection unit 240 is relatively small.For example, the signal of the detected supplied power may have a lowamplitude. In order to identify a HIGH value or a LOW value of thedetected supplied power, and demodulate the message based on theidentified value, a magnitude of amplitude of the detected suppliedpower may need to be amplified to be greater than the predeterminedvalue. For example, the HIGH value or the LOW value may be determined bycomparing the detected supplied power and the reference power. When thedetected supplied power is greater than the reference power, the HIGHvalue may be determined, and otherwise the LOW value may be determinedThe reference power may be determined based on the various applications.

The ripple removing unit 263 removes a ripple signal included in thedetected supplied power. The ripple signal may be generated when asignal passes through a circuit.

The comparison unit 265 compares the signal of the detected suppliedpower to the predetermined reference signal to output the HIGH value orthe LOW value of the detected supplied power. For example, when thesignal of the detected supplied power is greater than the predeterminedreference signal, the comparison unit 265 may output the HIGH value, andotherwise, the comparison unit 265 may output the LOW value. Thepredetermined reference signal may be provided by the control unit 270.The predetermined reference signal may include a predetermined fixedvalue, or may include a smallest value in the detected supplied power,which may be variable based on the change in the amount of the detectedsupplied power. The demodulation unit 260 demodulates the messagereceived from the target device based on the HIGH value or the LOW valueof the detected supplied power that is output from the comparison unit265.

The control unit 270 senses the change in the impedance 230 of thetarget device. For example, the control unit 270 may sense the change inthe impedance 230 of the target device through matching networks of thesource device and the target device, being improperly matched. Also, thecontrol unit 270 controls the power supplied to the PA 220 based on thechange in the impedance 230 of the target device.

FIG. 3 illustrates a detailed example of a communication apparatus usinga wireless power. The communication apparatus may be implemented in thesource device 110 of FIG. 1. The communication apparatus includes amatching network 310, a detection unit 320, an amplification unit 330, aripple removing unit 340, and a comparison unit 350, along with thefrequency generating unit 210, the PA 220, the AC/DC converter 250, andthe control unit 270 of FIG. 2.

Referring to FIG. 3, the matching network 310 matches an input impedanceof a target device and an impedance output from the PA 220. The inputimpedance is changed when an impedance of the target device is changed.

In examples, the detection unit 320 may detect a voltage applied to bothends of a resistor Rs to detect a supplied voltage that is input intothe PA 220. A level of a power input into the PA 220 may be determinedbased on the supplied voltage. A transistor may be used instead of theresistor Rs, and the detection unit 320 may detect a voltage applied toboth ends of an On-resistance (R_(on)) of the transistor to detect thesupplied voltage. The detection unit 320 may detect the supplied voltageusing a line impedance instead of the resistor Rs. Also, the detectionunit 320 may detect a current flowing through the resistor Rs to detecta supplied current that is input into the PA 220.

The amplification unit 330 amplifies the voltage applied to the bothends of, e.g., the resistor Rs, to be greater than a predeterminedvalue. For example, the amplification unit 330 includes resistors R1 andR2, a differential amplifier and one or more various transistors, whichare well-known in the same technical field.

The ripple removing unit 340 removes a ripple signal included in theamplified voltage, using a capacitor C₂ and a resistor RL. Thecomparison unit 350 compares the voltage received from the rippleremoving unit 340 to a predetermined reference signal 351, to output aHIGH value or a LOW value of the received voltage. The predeterminedreference signal 351 may be provided by the control unit 270. Thepredetermined reference signal 351 may include a predetermined fixedvalue, or may include a minimum value of the detected supplied voltage.The comparison unit 350 includes a comparator to perform the comparison.

A capacitor C₁ removes a ripple signal included in a signal that isoutput from the comparison unit 350. The control unit 270 (and/or thedemodulation unit 260 of FIG. 2) demodulates a message received from thetarget device based on the HIGH value or the LOW value that is outputfrom the comparison unit 350.

FIG. 4 illustrates another example of a communication apparatus using awireless power. The communication apparatus may be implemented in thesource device 110 of FIG. 1. Referring to FIG. 4, the communicationapparatus includes a conversion unit 410, a modulation unit 420, acontrol unit 430, a frequency generating unit 440, a PA 450, and amatching network 460.

In examples, the conversion unit 410 may convert an AC voltage to a DCvoltage of a plurality of levels, using a switching pulse signal. The ACvoltage may be supplied from, for example, an external power supply. Theconversion unit 410 may convert the AC voltage to the DC voltage, usinga switching mode power supply (SMPS).

The control unit 430 controls the DC voltage of the plurality of levels.For example, the control unit 430 may control a duration and/or amagnitude (e.g., of amplitude) of the DC voltage.

In another example, the control unit 430 may generate a digital controlsignal and convert the digital control signal to an analog controlsignal to control the DC voltage of the plurality of levels. In thisexample, the control unit 430 may include a digital-to-analog (D/A)converter (not shown). The D/A converter may convert the digital controlsignal to the analog control signal. The control unit 430 may controlthe magnitude of the DC voltage based on the analog control signal. Forexample, when a magnitude of the analog control signal is multiplied bythe magnitude of the DC voltage, the magnitude of the DC voltage maydecrease or increase.

In still another example, the control unit 430 may control the DCvoltage of the plurality of levels based on controlling a pulse width ofthe DC voltage. In this example, the control unit 430 may generate apulse-width modulation signal so that the DC voltage may be input intothe PA 450 during one or more predetermined time periods. Thepulse-width modulation signal may refer to a signal including pulseshaving different pulse widths. For example, when the pulse-widthmodulation signal is multiplied by the DC voltage, an operationalvoltage used to operate the PA 450, may be supplied to the PA 450 for arelatively long time during a time period, and for a relatively shorttime during another time period.

The control unit 430 transfers data in a form of a pulse signal to themodulation unit 420. The data is of a the source device and is to betransmitted to the target device. The modulation unit 420 modulates thedata based on the controlled DC voltage of the plurality of levels. Thecontrolled DC voltage may have a magnitude and/or a duration that may bechanged depending on cases. In more detail, the modulation unit 420modulates the data by mapping the data to include the magnitude and/orthe duration of the controlled DC voltage. Also, the modulation unit 420modulates the data by synthesizing the data in the form of the pulsesignal received from the control unit 430 with the controlled DCvoltage.

In addition, the modulation unit 420 modulates the data based on anindex of a power output from the PA 450. In examples, the control unit430 may change the index of the power output from the PA 450, bycontrolling a magnitude and/or a duration of a signal input into the PA450. Also, the control unit 430 may change the index of the power outputfrom the PA 450, by changing a magnitude and/or a duration of theoperational voltage used to operate the PA 450. The modulation unit 420modulates the data based on the index that may be changed. The indexwill be further described with reference to FIG. 10.

The frequency generating unit 440 generates a signal with a resonancefrequency. The resonance frequency may be determined by the control unit430. The PA 450 amplifies the input signal with the resonance frequencyto a magnitude (e.g., of amplitude) corresponding to a request of thetarget device. The PA 450 outputs a power, using the input signal withthe resonance frequency as an input signal, and the controlled DCvoltage of the plurality of levels as an operational signal. The PA 450may receive the controlled DC voltage from the conversion unit 410and/or via the modulation unit 420. The matching network 460 matches aninput impedance of the target device and an impedance output from the PA450.

FIG. 5 illustrates another detailed example of a communication apparatususing a wireless power. The communication apparatus may be implementedin the source device 110 of FIG. 1. Referring to FIG. 5, thecommunication apparatus includes an SMPS 510, a control unit 520, and atransistor 530, along with the frequency generating unit 440, the PA450, and the matching network 460 of FIG. 4.

The SMPS 510 converts an AC voltage to a DC voltage, using a switchingpulse signal. The AC voltage may be supplied from, for example, anexternal power supply.

The control unit 520 controls a voltage output from the transistor 530.For example, the control unit 520 may control the voltage output fromthe transistor 530 by controlling a voltage that is input into thetransistor 530, using one of the examples described with reference toFIG. 4. In another example, the control unit 520 may control the voltageoutput from the transistor 530 based on a difference between a voltagethat is input from the control unit 520 into the transistor 530 and avoltage that is input from the SMPS 510 into the transistor 530. Thevoltage output from the transistor 530 is a voltage supplied to the PA450. Data of the source device to be transmitted to a target device, ismodulated based on an operational voltage of various levels that isinput into the PA 450 (e.g., the voltage supplied to the PA 450) andthat is controlled by the control unit 520.

FIG. 6 illustrates still another example of a communication apparatususing a wireless power. The communication apparatus may be implementedin the source device 110 of FIG. 1. Referring to FIG. 6, thecommunication apparatus includes a frequency generating unit 610, amodulation unit 620, a control unit 630, a PA 640, a conversion unit650, and a matching network 660.

The frequency generating unit 610 generates a signal with a resonancefrequency. The resonance frequency may be determined by the control unit630. The PA 640 amplifies the input signal with the resonance frequencyto a magnitude (e.g., of amplitude) corresponding to a request of atarget device. The PA 640 outputs a power, using the input signal withthe resonance frequency as an input signal, and a signal output from theconversion unit 650 as an operational signal. The matching network 660matches an input impedance of the target device and an impedance outputfrom the PA 640.

The conversion unit 650 converts an AC voltage to a DC voltage of aplurality of levels, using a switching pulse signal. The AC voltage maybe supplied from, for example, an external power supply.

The control unit 630 provides, to the modulation unit 620, a pulsesignal that is synthesized with the resonance frequency. The controlunit 630 controls a duration and/or a magnitude (e.g., of amplitude) ofthe pulse signal.

In an example, the control unit 630 may generate a digital controlsignal and convert the digital control signal to an analog controlsignal, and may control the pulse signal based on the analog controlsignal. The control unit 630 may include a D/A converter (not shown).The D/A converter may convert the digital control signal to the analogcontrol signal. The control unit 630 may control the magnitude of thepulse signal based on the analog control signal.

In another example, the control unit 630 may control the pulse signalbased on controlling a pulse width of the pulse signal. In this example,the control unit 630 may generate a pulse width modulation signal sothat the pulse signal may be input into the PA 640 during one or morepredetermined time periods. The pulse width modulation signal may referto a signal including pulses having different pulse widths. For example,when the pulse signal with the resonance frequency is multiplied by thepulse width modulation signal, an input voltage may be supplied to thePA 640 for a relatively long time during a time period, and for arelatively short time during another time period.

The modulation unit 620 modulates data by synthesizing the input signaland the pulse signal. The data is of the source device and is to betransmitted to the target device. The pulse signal may have a magnitudeand/or a duration that may be changed depending on cases. Also, themodulation unit 620 modulates the data by mapping the data to includethe magnitude and/or the duration of the pulse signal.

FIG. 7 illustrates a example of the modulation unit 620 of FIG. 6.Referring to FIG. 7, the modulation unit 620 includes a plurality ofattenuators, for example, an attenuator 710, an attenuator 720, anattenuator 730, an attenuator 740, and an attenuator 750. In thisexample, the attenuator 710 may reduce a magnitude (e.g., of amplitude)of an input signal generated by the frequency generating unit 610 by 0.5decibels (dB). The attenuator 720 may reduce the magnitude of the inputsignal by 1 dB. The attenuator 730 may reduce the magnitude of the inputsignal by 2 dB. The attenuator 740 may reduce the magnitude of the inputsignal by 4 dB. The attenuator 750 may reduce the magnitude of the inputsignal by 8 dB.

The modulation unit 620 controls electrical connections between theattenuators 710 through 750 and the frequency generating unit 610, usingswitches. For example, the modulation unit 620 may control a switch 751to connect the attenuators 710 through 750 with the frequency generatingunit 610 to reduce the magnitude of the input signal by a sum total of15.5 dB. The modulation unit 620 modulates data by attenuating the inputsignal by a predetermined magnitude, using the attenuators 710 through750.

FIG. 8 illustrates another example of the modulation unit 620 of FIG. 6.Referring to FIG. 8, the modulation unit 620 includes a plurality ofdiodes, for example, a diode 830, a diode 840, a diode 850, and a diode860. The modulation unit 620 increases or decreases a magnitude of aninput signal generated by the frequency generating unit 610 based on adifference between a voltage Vs applied to the diode 830 and the diode860 and a voltage Vcon applied to a position 880 between the diode 840and the diode 850.

In more detail, when the voltage Vs at a position 870 is greater thanthe voltage Vcon at the position 880, a reverse bias is applied to thediode 840. When the voltage Vs at a position 890 is greater than thevoltage Vcon at the position 880, a reverse bias is applied to the diode850. Thus, in this case, the diode 840 and the diode 850 operate likecapacitors. When the voltage Vcon at the position 880 is greater thanthe voltage Vs at the position 870, a forward bias is applied to thediode 840. When the voltage Vcon at the position 880 is greater than thevoltage Vs at the position 890, a forward bias is applied to the diode850. Thus, in this case, the diode 840 and the diode 850 operate likeresistors. The resistors may be referred to as forward resistors.

The control unit 630 controls the voltage Vcon to enable a forward biasto be applied to the diode 840 and the diode 850. A value of a forwardresistor is variable based on a magnitude of the controlled voltageVcon. The modulation unit 620 modulates data, using the variable forwardresistors. That is, the modulation unit 620 increases or decreases themagnitude of the input signal generated by the frequency generating unit610 using the variable forward resistors.

The matching network 810 matches an input impedance of the modulationunit 620 and an impedance output from the frequency generating unit 610.The matching network 820 matches an input impedance of the target deviceand an impedance output from the modulation unit 620.

FIG. 9 illustrates an example of a relationship between a voltage thatis supplied to a power amplifier and a power that is output from thepower amplifier. The power output from the PA increases as the voltagesupplied to the PA increases. The voltage supplied to the PA may be anoperational voltage of the PA or may be a voltage input into the PA.Since the output power is proportional to the supplied voltage, acommunication apparatus using a wireless power may demodulate a messagereceived from a target device based on a change in the supplied voltage,and may modulate a message of a source device by changing the suppliedvoltage.

When an impedance of the target device is changed, the power output fromthe PA may be changed. In this example, since the voltage supplied tothe PA may need to be changed in order to change the power from the PA,the communication apparatus may demodulate a message received from thetarget device based on a change in an amount the supplied voltagecorresponding to load modulation. Also, the communication apparatus maymodulate a message of the source device by changing a magnitude and/or aduration of the supplied voltage. The output power output may be changedbased on the change in the supplied voltage, and the target device maydemodulate the message of the source device based on the change in anamount of the output power.

FIG. 10 illustrates an example of a modulating process using a powerthat is output from a power amplifier. Line A indicates a maximumamplitude of the output power, and line B indicates a minimum amplitudeof the output power. An index of the output power may be a percentage ofa quotient of a difference between the maximum amplitude and the minimumamplitude, and a sum of the maximum amplitude and the minimum amplitude,as expressed by Equation 1.

$\begin{matrix}{{Index} = {\frac{A - B}{A + B} \times 100\%}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

A communication apparatus using a wireless power may modulate data basedon the index of the output power. Since the index may be determinedbased on the maximum amplitude and the minimum amplitude of the outputpower, the communication apparatus may modulate data by adjusting themaximum amplitude and the minimum amplitude of the output power. Themaximum amplitude and the minimum amplitude of the output power may bedetermined based on a voltage that may be input or supplied to the PA.In more detail, the communication apparatus may adjust the maximumamplitude and the minimum amplitude of the output power based on amagnitude and/or a duration of the input voltage or the suppliedvoltage.

FIG. 11 illustrates an example of a communication method using awireless power. At step 1110, a source device senses a change in animpedance of a target device. For example, the source device may sensethe change in the impedance of the target device through matchingnetworks of the source device and the target device being improperlymatched or being mismatched.

At step 1120, the source device controls an AC/DC converter based on thechange in the impedance of the target device. In more detail, the sourcedevice controls a power that is output from the AC/DC converter to be apower corresponding to a request of the target device. The power outputfrom the AC/DC converter is provided to a PA as a power supplied to thePA.

At step 1130, the source device detects the power supplied to the PAthat is output from the AC/DC converter and is input into the PA. Inexamples, the source device may detect a voltage or a current suppliedto the PA. The source device may detect the supplied power based ondetecting a voltage applied to both ends of a resistor. Also, the sourcedevice may detect the supplied power based on detecting a voltageapplied to both ends of an ON-resistance (R_(on)) of a transistor.Further, the source device may detect the supplied power based ondetecting a voltage applied to both ends of a line impedance.

At step 1140, the source device demodulates a message received from thetarget device based on a change in an amount of the detected suppliedpower. Since the supplied power may be changed based on the change inthe impedance of the target device, the source device may demodulate themessage by comparing the change in the amount (e.g., a signal) of thedetected supplied power to a predetermined reference signal.

In more detail, the source device amplifies the detected supplied powerto be greater than a predetermined value. The source device compares thedetected supplied power to the predetermined reference signal to outputa HIGH value or a LOW value of the detected supplied power. The sourcedevice demodulates the message received from the target device based onthe output HIGH value or the output LOW value.

FIG. 12 illustrates another example of a communication method using awireless power. At step 1210, a source device converts an AC voltage toa DC voltage of a plurality of levels, using a switching pulse signal.

At step 1220, the source device controls the DC voltage of the pluralityof levels to be supplied to a PA. In examples, the source device maycontrol a magnitude and/or a duration of the DC voltage. The sourcedevice may generate a digital control signal and may convert the digitalcontrol signal to an analog control signal, and may control the DCvoltage based on the analog control signal. The source device maycontrol the DC voltage by controlling a pulse width of the DC voltage.

At step 1230, the source device modulates data based on the controlledDC voltage of the plurality of levels. In examples, the source devicemay modulate the data by mapping the data to the magnitude and/or theduration of the DC voltage of the plurality of levels. The source devicemay modulate the data based on an index of a power that may be outputfrom the PA.

FIG. 13 illustrates an example of an electric vehicle charging system1300. The electric vehicle charging system 1300 includes a source system1310, a source resonator 1320, a target resonator 1330, a target system1340, and an electric vehicle battery 1350.

The electric vehicle charging system 1300 may have a similar structureto the wireless power transmission system of FIG. 1. The source system1310 and the source resonator 1320 in the electric vehicle chargingsystem 1300 may function as a source device. Additionally, the targetresonator 1330 and the target system 1340 in the electric vehiclecharging system 1300 may function as a target device.

The source system 1310 may include, for example, an AC/DC converter, apower detector, a power converter, a control/communication unit,similarly to the source device 110 of FIG. 1. The target system 1340 mayinclude, for example, a rectification unit, a DC/DC converter, a switchunit, a charging unit, and a control/communication unit, similarly tothe target device 120 of FIG. 1.

The source system 1310 generates power based on a type of an electricvehicle, a capacity of the electric vehicle battery 1350, and/or acharging state of the electric vehicle battery 1350. The source system1310, via the source resonator 1320, may supply the generated power, viathe target resonator 1330, to the target system 1340. The target system1340 charges the electric vehicle battery 1350. The electric vehiclecharging system 1300 may use a resonance frequency in a band of a fewkilohertz (KHz) to tens of MHz.

The source system 1310 controls the source resonator 1320 and the targetresonator 1330 to be aligned. For example, when the source resonator1320 and the target resonator 1330 are not aligned, a controller of thesource system 1310 may transmit a message to the target system 1340, andmay control alignment between the source resonator 1320 and the targetresonator 1330.

For example, when the target resonator 1330 is not located in a positionenabling maximum magnetic resonance, the source resonator 1320 and thetarget resonator 1330 may not be aligned. When the electric vehiclevehicle does not stop accurately, the source system 1310 may induce aposition of the electric vehicle to be adjusted, and may control thesource resonator 1320 and the target resonator 1330 to be aligned.

The source system 1310 and the target system 1340 may transmit orreceive an ID of the electric vehicle, and/or may exchange variousmessages through communication. The descriptions of FIGS. 2 through 12may be applied to the electric vehicle charging system 1300. However,the electric vehicle charging system 1300 may use a resonance frequencyin a band of a few KHz to tens of MHz, and may transmit power that isequal to or higher than tens of watts to charge the electric vehiclebattery 1350.

FIGS. 14A through 15B illustrate examples of applications in which awireless power receiver and a wireless power transmitter may be mounted.

FIG. 14A illustrates an example of wireless power charging between a pad1410 and a mobile terminal 1420, and FIG. 14B illustrates an example ofwireless power charging between pads 1430 and 1440 and hearing aids 1450and 1460.

In an example, a wireless power transmitter may be mounted in the pad1410, and a wireless power receiver may be mounted in the mobileterminal 1420. The pad 1410 may be used to charge a single mobileterminal, namely the mobile terminal 1420.

In another example, two wireless power transmitters may be respectivelymounted in the pads 1430 and 1440. The hearing aids 1450 and 1460 may beused for a left ear and a right ear, respectively. In this example, twowireless power receivers may be respectively mounted in the hearing aids1450 and 1460.

FIG. 15A illustrates an example of wireless power charging between anelectronic device 2140 that is inserted into a human body, and a mobileterminal 1520. FIG. 15B illustrates an example of wireless powercharging between a hearing aid 1530 and a mobile terminal 1540.

In an example, a wireless power transmitter and a wireless powerreceiver may be mounted in the mobile terminal 1520. In this example,another wireless power receiver may be mounted in the electronic device2140. The electronic device 2140 may be charged by receiving power fromthe mobile terminal 1520.

In another example, a wireless power transmitter and a wireless powerreceiver may be mounted in the mobile terminal 1540. In this example,another wireless power receiver may be mounted in the hearing aid 1530.The hearing aid 1530 may be charged by receiving power from the mobileterminal 1540. Low-power electronic devices, for example Bluetoothearphones, may also be charged by receiving power from the mobileterminal 1540.

FIG. 16 illustrates an example of a wireless power transmitter and awireless power receiver.

In FIG. 16, a wireless power transmitter 1610 may be mounted in each ofthe pads 1430 and 1440 of FIG. 14B. Additionally, the wireless powertransmitter 1610 may be mounted in the mobile terminal 1540 of FIG. 15B.

In addition, a wireless power receiver 1620 may be mounted in each ofthe hearing aids 1450 and 1460 of FIG. 14B.

The wireless power transmitter 1610 may have a similar configuration tothe source device 110 of FIG. 1. For example, the wireless powertransmitter 1610 may include a unit configured to transmit power usingmagnetic coupling.

As illustrated in FIG. 16, the wireless power transmitter 1610 includesa communication/tracking unit 1611. The communication/tracking unit 1611may communicate with the wireless power receiver 1620, and may controlan impedance and a resonant frequency to maintain a wireless powertransmission efficiency. Additionally, the communication/tracking unit1611 may perform similar functions to the power converter 114 and thecontrol/communication unit 115 of FIG. 1.

The wireless power receiver 1620 may have a similar configuration to thetarget device 120 of FIG. 1. For example, the wireless power receiver1620 may include a unit configured to wirelessly receive power and tocharge a battery. As illustrated in FIG. 16, the wireless power receiver1620 includes a target resonator, a rectifier, a DC/DC converter, and acharging circuit. Additionally, the wireless power receiver 1620 mayinclude a control/communication unit 1623.

The communication/control unit 1623 may communicate with the wirelesspower transmitter 1610, and may perform an operation to protectovervoltage and overcurrent.

The wireless power receiver 1620 may include a hearing device circuit1621. The hearing device circuit 1621 may be charged by the battery. Thehearing device circuit 1621 may include a microphone, ananalog-to-digital converter (ADC), a processor, a digital-to-analogconverter (DAC), and a receiver. For example, the hearing device circuit1621 may have the same configuration as a hearing aid.

According to the teachings above, there is provided an apparatus andmethod in which a modulated message received from a target device may berestored or demodulated more stably, using an operational voltage of apower amplifier. Also, data may be restored stably without frequencyinterference, based on a change in an amount of power supplied to thepower amplifier, at a resonance frequency identical to a frequency atwhich a power may be transmitted. Further, problems of a DC offset, aleakage current, and/or other types of problems may be resolved, and aBit Error Rate (BER) in communication may be improved, by performingmodulation and demodulation using a voltage or a current supplied to thepower amplifier.

The units described herein may be implemented using hardware componentsand software components. For example, the hardware components mayinclude microphones, amplifiers, band-pass filters, audio to digitalconvertors, and processing devices. A processing device may beimplemented using one or more general-purpose or special purposecomputers, such as, for example, a processor, a controller and anarithmetic logic unit, a digital signal processor, a microcomputer, afield programmable array, a programmable logic unit, a microprocessor orany other device capable of responding to and executing instructions ina defined manner. The processing device may run an operating system (OS)and one or more software applications that run on the OS. The processingdevice also may access, store, manipulate, process, and create data inresponse to execution of the software. For purpose of simplicity, thedescription of a processing device is used as singular; however, oneskilled in the art will appreciated that a processing device may includemultiple processing elements and multiple types of processing elements.For example, a processing device may include multiple processors or aprocessor and a controller. In addition, different processingconfigurations are possible, such a parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, for independently orcollectively instructing or configuring the processing device to operateas desired. Software and data may be embodied permanently or temporarilyin any type of machine, component, physical or virtual equipment,computer storage medium or device, or in a propagated signal wavecapable of providing instructions or data to or being interpreted by theprocessing device. The software also may be distributed over networkcoupled computer systems so that the software is stored and executed ina distributed fashion. In particular, the software and data may bestored by one or more computer readable recording mediums. The computerreadable recording medium may include any data storage device that canstore data which can be thereafter read by a computer system orprocessing device. Examples of the non-transitory computer readablerecording medium include read-only memory (ROM), random-access memory(RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storagedevices. Also, functional programs, codes, and code segments foraccomplishing the examples disclosed herein can be easily construed byprogrammers skilled in the art to which the examples pertain based onand using the flow diagrams and block diagrams of the figures and theircorresponding descriptions as provided herein.

As a non-exhaustive illustration only, a terminal or device describedherein may refer to mobile devices such as a cellular phone, a personaldigital assistant (PDA), a digital camera, a portable game console, andan MP3 player, a portable/personal multimedia player (PMP), a handhelde-book, a portable laptop PC, a global positioning system (GPS)navigation, a tablet, a sensor, and devices such as a desktop PC, a highdefinition television (HDTV), an optical disc player, a setup box, ahome appliance, and the like that are capable of wireless communicationor network communication consistent with that which is disclosed herein.

A number of examples have been described above. Nevertheless, it will beunderstood that various modifications may be made. For example, suitableresults may be achieved if the described techniques are performed in adifferent order and/or if components in a described system,architecture, device, or circuit are combined in a different mannerand/or replaced or supplemented by other components or theirequivalents. Accordingly, other implementations are within the scope ofthe following claims.

1. An apparatus for communication using a wireless power, comprising: anamplifier configured to amplify an input signal based on a powersupplied to the amplifier; a control unit configured to detect a changein an impedance of a target device, and to change the power based on thechange in the impedance; and a demodulation unit configured to receive amessage from the target device, and to demodulate the message based onthe changed power.
 2. The apparatus of claim 1, further comprising: adetection unit configured to detect the changed power.
 3. The apparatusof claim 2, wherein: the detection unit further comprises a resistor, oran ON-resistance of a transistor, or a line impedance, or anycombination thereof; and the detection unit is further configured todetect a voltage applied to the resistor, or the ON-resistance of atransistor, or the line impedance, or any combination thereof, to detectthe changed power.
 4. The apparatus of claim 1, wherein the demodulationunit comprises: an amplification unit configured to amplify the changedpower to be greater than a predetermined value.
 5. The apparatus ofclaim 1, wherein the demodulation unit comprises: a ripple signalremoving unit configured to remove a ripple signal comprised in thechanged power.
 6. The apparatus of claim 1, wherein: the demodulationunit comprises a comparison unit configured to compare the changed powerto a predetermined reference signal, and to determine a HIGH value or aLOW value of the changed power based on a result of the comparison; andthe demodulation unit is further configured to demodulate the messagebased on the HIGH value or the LOW value.
 7. An apparatus forcommunication using a wireless power, comprising: an amplifierconfigured to amplify an input signal based on a direct current (DC)voltage of a plurality of levels that is supplied to the amplifier; acontrol unit configured to control the DC voltage; and a modulation unitconfigured to modulate data based on the controlled DC voltage.
 8. Theapparatus of claim 7, further comprising: a conversion unit configuredto receive an alternating current (AC) voltage, and to convert the ACvoltage to the DC voltage based on a switching pulse signal.
 9. Theapparatus of claim 7, wherein: the amplifier is further configured tooutput a power based on the amplified signal; and the modulation unit isfurther configured to modulate the data based on an index of the power.10. The apparatus of claim 7, wherein the control unit is furtherconfigured to generate a digital control signal, to convert the digitalcontrol signal to an analog control signal, and to control the DCvoltage based on the analog control signal.
 11. The apparatus of claim7, wherein the control unit is further configured to control a pulsewidth of the DC voltage.
 12. The apparatus of claim 7, wherein: theamplifier is further configured to receive an input voltage and anoperational voltage; and the control unit is further configured tocontrol a magnitude of the input voltage or a magnitude of theoperational voltage.
 13. A method for communication using a wirelesspower, comprising: detecting a change in an impedance of a targetdevice; changing a power supplied to an amplifier based on the change inthe impedance; and demodulating a message received from the targetdevice based on the changed power.
 14. The method of claim 13, furthercomprising: detecting the changed power.
 15. The method of claim 13,wherein the demodulating comprises amplifying the changed power to begreater than a predetermined value.
 16. The method of claim 13, whereinthe demodulating comprises: comparing the changed power to apredetermined level; determining a HIGH value or a LOW value of thechanged power based on a result of the comparing; and demodulating themessage based on the HIGH value or the LOW value.
 17. A method forcommunication using a wireless power, comprising: controlling a directcurrent (DC) voltage of a plurality of levels that is supplied to anamplifier; and modulating data based on the controlled DC voltage. 18.The method of claim 17, further comprising: converting an alternatingcurrent (AC) voltage to the DC voltage based on a switching pulsesignal.
 19. The method of claim 17, wherein the modulating comprisesmodulating the data based on an index of a power output from theamplifier.
 20. The method of claim 17, wherein the controllingcomprises: generating a digital control signal; converting the digitalcontrol signal to an analog control signal; and controlling the DCvoltage based on the analog control signal.
 21. The method of claim 17,wherein the controlling comprises controlling a pulse width of the DCvoltage.